Faszination Licht. Entwicklungstrends im LED Packaging. Dr. Rafael Jordan Business Development Team. Dr. Rafael Jordan, Business Development Team

Transcription

1 Faszination Licht Entwicklungstrends im LED Packaging Dr. Rafael Jordan Business Development Team

2 Agenda Introduction Hermetic Packaging Large Panel Packaging Failure Analysis

3 Agenda Introduction Hermetic Packaging Large Panel Packaging Failure Analysis

4 FRAUNHOFER IZM RESEARCH FOR TOMORROW S PRODUCTS Dr. Rafael Name Jordan Business Abteilung Unit Photonics

5 Overview Fraunhofer Gesellschaft 67 institutes 23,000 employees app. 2 billion turnover app. 70% contract research Information Technology Light & Surfaces Life Sciences Micro Electronics Production Defense & Security Materials & Components

6 Fraunhofer IZM Facts Figures Mio. turnover 77 % contract research 389 employees (230 full time, 159 PhD, trainee) Locations Berlin Oberpfaffenhofen Dresden University Cooperation Long term contract with Technical University of Berlin Research Center Microperipheric Technologies Approx. 90 additional staff Joint use of equipment, facilities and infrastructure Director Prof. K.-D. Lang Material characterization Process evaluation Reliability testing Failure analysis Sample production Training courses

7 Mission Fraunhofer IZM Bringing Microelectronics into Application

8 LED Packaging Tasks Filling Wire Bond 1st & 2nd Level Interconnect Optics Chip Board Phosphor Submount Underfill E v i r o n m e n t Power Cooling

9 Agenda Introduction Hermetic Packaging Large Panel Packaging Failure Analysis

10 Hermetic Concept electrical vias electrical and thermal vias

11 Silicon Substrate Wafer with TSVs Silicon Substrate Wafer backside view on soldering pads Silicon Substrate Wafer overview

12 Silicon Glass Cap Wafer Si/glass cap wafer with tapered reflector edges Si/glass cap wafer overview

13 Silicon Substrate Silicon Substrate with 4 Component Positions with AuSn Silicon Substrate with Intermediate Glass Carrier

14 Glas Cap Top View von Glass Cap Side View on Glas Cap

15 Die and Wire Bonded LEDs Top View Wire Bonded RGB LEDs (one position free, e.g. for photodiode) Side View Wire Bonded White LEDs

16 Full Assembled Packages RGB LED Package White LED Package

17 Solder Interconnection Analysis Glas Cap on Silicon Substrate Side View Glas Cap on Silicon Substrate with Intermediate Glass Carrier

18 Solder Interconnection Analysis x-ray Overview x-ray Focus Complete void free process!

19 Solder Interconnection Analysis not remalting solder joint for further assembly Dielectric Layer (no gap!) Glas Cap on Silicon Substrate Side View Glas Cap on Silicon Substrate

20 Acknowledgements EnLight stands for Energy efficient & intelligent lighting systems and was an EU funded and Philips Lighting coordinated project which ran from 2011 to The consortium consisted of 27 leading European companies and academic institutions from across the entire lighting value chain.

21 Agenda Introduction Hermetic Packaging Large Panel Packaging Failure Analysis

22 New LED Packaging Approach for Panel Level Packaging Lighting Panel conventional LED packaging? New Packaging approach required Large area manufacturing Low cost

23 Two Panel Level Packaging Concepts Collective Transferbonding Wafer to Panel Transferbonding using temporary carrier Top side contact through (wire bonding) or lamination Pick & Place and Lamination Chip on Panel adhesive bonding Top side contact through lamination

24 Two Panel Level Packaging Concepts Collective Transferbonding Wafer to Panel Transferbonding using temporary carrier Top side contact through (wire bonding) or lamination Pick & Place and Lamination Chip on Panel adhesive bonding Top side contact through lamination

25 Collective Transferbonding - Process Flow

26 Collective Transferbonding CarrierChips: 118 carrier on wafer 165 x 165 (27225 Chips on carrier) > 3 Mio. Chips on wafer Chipsize 75 µm Chips are sticked with PI auf Carrier

27 Assembly concept for small LED-Chips Temporarily Bonding of LEDs on Intermediate Carrier Handling of small Chips (70 µm edge length) Collective Soldering high-precision and plane-parallel Assembly

28 Collective Transferbonding with functional LEDs Components: LED-Carrier Pi-layer FunctionalLED-Chip with Au-metallization PCB with Cu structure 1.Step: stencil printing of solderpaste (SAC) Topview on LED Carrier Crosssection of PCB with solder depot

29 Collective Transferbonding with functional LEDs 2.Step: Alignment between PCB and LED Carrier 3.Step: Collective Transferbonding PCB with aligned LED Carrier

30 Collective Transferbonding with functional LEDs 4.Step: vertical removing of LED- Carrier Assembled and wire bonded LEDs on a PCB 5.Step: Wire bonding

31 Demonstrators with functional LEDs Serial connections of 10 blue LEDs at about 25V

32 Two Panel Level Packaging Concepts Collective Transferbonding Wafer to Panel Transferbonding using temporary carrier Top side contact through (wire bonding) or lamination Pick & Place and Lamination Chip on Panel adhesive bonding Top side contact through lamination

33 Panel Level Packaging Concept LED with top and bottom contact pairwise connection of LEDs and z-feedthrougs (0 Ω- contact dies) at PCB by conductive adhesive (ICA) and on top by copper paths Assembling on PCBs of different sizes the whole sandwich is hold together by a polymeric adhesive layer

34 Process Flow Assembling of LEDs Electrical Contacting screen printing of ICA on structured PCB placing of adhesive layer and copper foil on top placing of LEDs and z-contacts lamination under pressure at elevated temperatures structuring of copper to connect top contacts of LEDs curing of ICA

35 Placement of LEDs LEDs > 200 µm² Pick-and-Place process with high yield ASM Siplace CA3 High precision placement (± 15 µm) on large area up to 24 x 18 / 610 x 457 mm² High Speed (> 5000 c.p.h.)

36 Lamination lamination of adhesive layer together with structured or unstructured copper foil temperature, pressure, vacuum temperature vacuum pressure time lamination cycle laminated unstructured board

37 Lamination lamination of adhesive layer together with structured or unstructured copper foil low pressure middle - optimum pressure high pressure

38 Electrical Connection Cu-structuring using PCB-processes laser drilled via to LED pad close up look to hole

39 Electrical Connection structured Cu-foil with Cu-via to contact pad of LED structured Cu-connection between LED and z-feedthrough Reliable electrical connection achieved using PCB based processes

40 Electrical Connection connection in series of 30 blue LEDs Successful proof of technology concept Cost-effective PCBtechnology used Boards of variable sizes can be produced easily Light-forming elements (white-light converters, lenses, diffusors..) can easily be added

41 Summary A new concept collective Transfer Bonding using a temporary Carrier was developed. Large LED Panels can be produced by Lamination and Board Technologies. Both Technologies were successfully developed for a functional demonstrator and has potential for low cost and large area lightning panels up to 24 x 18 / 610 x 457 mm²

42 Acknowledgements Results are partially achieved in the joint project Hi-Q-LED: OSRAM Opto Semiconductors GmbH, Regensburg Fraunhofer IAF, Freiburg Universität Ulm Fraunhofer IZM, Berlin ASEM Präzisionsautomaten GmbH, Dresden Cerion GmbH, Minden Fresnel Optics GmbH, Apolda OSRAM GmbH, München

43 Agenda Introduction Hermetic Packaging Large Panel Packaging Failure Analysis

44 Aging of Polymers 0,18 0,18 LED with polymer coated 0,15 LED reference 0,15 optical power [W/nm] 0,13 0,10 0,08 0,05 5h 59h 119h 269h 359h 449h optical power [W/nm] 0,13 0,10 0,08 0,05 5h 59h 119h 269h 359h 449h 0,03 0,03 0,00 0, wavelength [nm] wavelength [nm]

45 Aging of Polymers 442,0 442,0 441,5 LED reference 441,5 LED polymere coated 441,0 441,0 wavelength [nm] 440,5 440,0 439,5 wavelength [nm] 440,5 440,0 439,5 439,0 439,0 438,5 438,5 438, , time [h] time [h]

46 Aging of Polymers 1,0 LED with polymer coated optical power [W/nm] transmission [Io/Ii] absorbance [lg(1/t)] 0,8 0,6 0,4 0,2 emission 5h emission 269 h emission 509 h transmission at 269 h transmission at 509 h Absorbance at 269 h Absorbance at 509 h 0, Wellenlänge / nm

47 Delamination of filling

48 Delamination of filling

49 Delamination of glued interface cross section ball bond

50 Delamination of ball bond SEM of cross section ball bond interface

51 Multiple interfaces to take care on

52 Damage of die overview focus below epilayer

53 Inhomogeneous amount of pores

54 Brittle solder alloys Pb Sn

55 Risk of the AuSn 4 Phase 1.1 degradation / I/I B at 150 C C at 150 C D at 200 C aging / h C & D : Au80Sn20 B : Au10Sn90

56 Brittle solder alloys Sn

57 Gap inside solder interconnect

58 Local overheating

59 Cracks in encapsulant Failure due to overheating: cracks in the epoxy mold due to CTE mismatch laser scanning fluorescence microscopic analysis of cracks

60 Cracks and collapsed pores

61 Thank you for you Attention! Dr. Rafael Jordan Business Development Team Tel.: +49 (30) Joseph Fraunhofer, (* 6. March 1787; 7. June 1826)